Abstract: In order to raise fitting accuracy of the existing modified continuous functions for slope mass rating (SMR), based on the least-squares-fit algorithm, the table-form-rating SMR was modified by using new continuous functions. Continuous fitting functions of ratings for point-load strength, uniaxial compressive strength, rock quality designation, discontinuity spacing, persistence, separation width, filling thickness and geometric correction factor for discontinuity and slope surface were proposed. These proposed functions were used for the fitting analyses of 57 slopes from hydropower stations, mines and highway projects. The fitting result shows that the residual standard deviation is 2.180 and the correlation coefficient is 0.996 7, and compared with other modified SMR systems, rating result of the SMR system modified by using the above continuous functions is closest to result of the table-form-rating SMR system.